Rotary pump, compressor, motor, or the like



July 24, 1951 F. w. MCcoMBIE 2,551,809

ROTARY PUMP, COMPRESSOR, MoToR 0R THE Lm:

:fwfirc wir E@dErtN/ValterMECumhiay Inf/M ATT JRNEY July 24, 1951 F w, MCCOMBE 2,561,809

ROTARY PUMP, COMPRESSOR, MOTOR OR THE LIKE Filed April 7, 1948 2 Sheets-Sheet 2 [JJ il' y/ ttorney Patented July 24,A 1951 ROTARY PUMP, COMPRESSOR, MOTOR, OR THE LIKE Frederick Walter McCombic, London, England,

assigner to Mclator Pumps Co Limited, Feltham, England Appumnm Apro 7, 194s, serai umass:

:nomini-rumena. 1941 'y Claim!) (Cl. 103-163) This invention relates to rotary pumps, compressors, motors or the like of the kind including a hollow member mounted for reciprocating movement within the pressure chamber of the pump or like casing, an eccentric rotatably mounted within said pressure chamber and surrounded by the hollow member, the eccentric engaging the Walls of the member at two oppositely disposed points on the periphery of the eccentric to provide a substantially fluid tight seal and by virtue of its rotational movement within said member give rise to the desired displacement or pumping effect, said hollow member being mounted for reciprocatory movement inthe plane of rotationV of the eccentric and in contact with a guiding surface located within the casing, the hollow member and guiding surface being formed with co-operatng valve ports which under the reciprocating action of the hollow member control the ilow of fluid to and from the displacement, pumping or expansion chamber formed by the interior of the hollow member enclosed by the eccentric and guiding surface. Such a construction forms the subject of our prior British Patent No. 592,432, corresponding to co-pending United States application Serial No. 666,363, led May 1, 1946.

It has been found that in use the pressure of the fluid within the pressure chamber is sumcient to maintain the necessary seal between the hollow member and the guiding surface but in the case of the construction of pump, compressor lor motor forming the subject of the above numbered patent the hollow memberincorporated a system of spring urged plungers bearing on fixed brackets mounted within the casing for the purpose of urging the chamber into contact with the guiding surface.

A rotary pump. compressor or motor of the kind set forth is characterised according to the present invention by a fixed guide portion co-operating with the side of the hollow member opposite to that contacting the guiding surface for maintaining the hollow member in close proximity to the guiding surface when the pump or the like is stationary or during the initial stage of starting up and wherein the hollow member during normal operation of the pump or the like is urged lby the pressure of fluid contained in the pressure chamber into contact with said guiding surface leaving a clearance space between the hollow member and fixed guide portion.

Although it is within the scope of the invention to utilise members such as the brackets disclosed by the specification and drawings of the patent above referred to or members attached to or forming part of the body of the pump or the like. as a xed stop, it is preferred to utilise the shaft or concentric portion of the rotor for thispurpose.

In order that the invention 'may be clearly understood and readily carried into effect, the invention is hereinafter described with reference to the accompanying drawings in which:

Fig. 1 is' a cross-sectional view taken vertically through the axis of an apparatus of the type embodying the present invention and on a plane correspondingto line |I of Fig. 2;

Fig. 2 is a cross-sectional view taken on line 2--2 of Fig. 1, and

Fig. 3 is an enlarged fragmentary cross-sectional view corresponding to the section of Fig. 2 and illustrating the embodiment of the invention.

The invention is shown applied to the construction of rotary pump forming the subject of our prior British Patent No. 592,432 the pump comprising a pump casing l containing a displacement chamber proper 2 constituted by a vertically reciprocable hollow member 3 and a contained eccentric 4 which engages the walls of the member 3 at two oppositely disposed points on theV periphery of the eccentric to provide a substantially fluid tight seal and by virtue of its rotational movement within the member give rise to the desired displacement eiiect. The eccentric I is fixed to a shaft 5 which in the case of the apparatus operating as a pump or compressor is rotatably driven from an external source of power supply. The walls of the member 3 lying on opposite sides of the eccentric are cut away to form slot-like openings S to provide the necessary clearance in a vertical direction to permitl of the necessary up and down reciprocating movement of the member 3. t

In the construction shown, the casing l is closed at one end by means of a cover 'I which is secured to the casing by means of studs 8 and nuts 9 and sandwiched between the cover and the casing is a separately constructed partition wall Ill, the casing i constituting the pressure chamber of the pump and the cover l the suction chamber. It will be appreciated that the hollow member and eccentric are situated on the pressure side of the partition l0.

The partition wall lo carries a flat plate Il against which the hollow member 3 bears, ports l2, I3, I4 and l5 being formed in the plate of which ports I2 and Il lead directly into the suction chamber inside the cover 1. whereas ports Il and I5 lead through ducts I6 and I1 respectively into the pressure chamber inside the casing I. The plate II, preferably, is removably mounted on the partition I0 by nuts and studs 20, a gasket 2| being interposed between the plate and partition for sealing and if necessary, for spacing purposes.

The suction chamber has an inlet connection 22 and the pressure chamber has an outlet connection 23 and it will be appreciated that rotational movement of the shaft 5 and its associated eccentric 4 will result in vertical reciprocating movement f the member 3 and alternate connection of the displacement chamber 2 with the suction chamber and pressure chamber by way of ports I2 and I4 and I3 and I5 respectively, the fluid as a result of the variation'in the eifective capacity of the displacement chamber, being drawn into the displacement chamber. and thereafter discharged into the pressure chamber.

The member 3 will be held in contact with the adjacent surface of the plate Il by the pressure of the fluid in the pressure chamber when the pump is in operation. 'I'he pump may comprise any desired number of pumping units, each including a member 3 and an eccentric 4, and for purposes of illustration three are shown in Fig. 1, it being understood that each of the units may be identical except that the eccentrics may be in angularly spaced phases.

As hereinbefore explained the member 3 is cut away to provide slot-like openings 6 for clearing the shaft, said openings being defined by edge portions I8 which are parallel to the front end surface of the member 3 bearing on the plate Il and disposed at a suitable distance from it to provide the required running clearance between the edge portions I3 and the shaft when the pump is operating, the shaft fulfilling the function of a fixed stop when the member 3 is no longer held in contact with the plate II by fluid pressure, as when the pump is inoperative or stationary, and during the initial stage of starting up. Immediately, however, the pump commences to pump fluid the pressure of the fluid in the pressure chamber will maintain the hollow member 3 in contact with the plate under a sufficient pressure to maintain an adequate fluid seal between the parts, the surface I8 owing to the adequate running clearance provided being then no longer in contact with the shaft.

In order to provide for adjustment of the running clearance for taking up wear in the parts, the shaft may beiadjustable in relation to the guiding surface or the guiding surface itself may be adjustable, the latter arrangement being preferred. In the case of the construction shown, where the guiding surface or plate I I forms virtually part of the partition wall I0 fixed to the pump body, the joint between the partition wall and body may be made with a number of gaskets or shims I9 one or more of which can be removed as required to bring the partition wall I0 and plate II closer to the shaft. Alternatively or in addition, spacer gaskets 2| may be inserted between the partition III and plate II.

It will be appreciated from the foregoing description that with the arrangement hereinbefore described there is now no longer any necessity to employ the brackets such as were disclosed in the prior patent and application above referred to, or their associated spring urged plungers for maintaining the hollow member in contact with the guiding surface during the initial stages of the pumps operation, thereby reducing wear on the parts and providing a simpler construction than that previously proposed.

I claim:

1. A machine for use as a pump, compressor. blower or motor, comprising a casing defining a high pressure chamber and having an inlet and an outlet, with said outlet in direct communication with said high pressure chamber, said casing having a wall defining a slideway, ports Ain said casing wall opening' through said slideway and respectively in communication with said inlet and said high pressure chamber, an eccentric, a. shaft for said eccentric journalled in said casing extending parallel with and spaced from said slideway, a hollow sleeve-like member having front and rear ends with slot-like openings through its side walls and defined by edge portions which are substantially parallel with the front end of said member, said hollow member being mounted in said casing between said shaft and casing wall with its front end against said slideway over said ports and with said shaft within said slot-like openings, said hollow member diametrically surrounding said eccentric to be reciprocated thereby over said slideway and alternately past said ports during its reciprocatory travel to control the flow of working fluid therethrough, said member interiorly cooperating with said slideway and the enclosed periphery of said eccentric to define an expansion chamber, said slideway being on the high pressure chamber side of said casing wall and said eccentric and hollow member being located in said high pressure chamber with said member maintained in sealing engagement with said slideway by pressure in said chamber, said edge portions of said openings being spaced from the slidable front end of said hollow member a distance slightly less than the spacing between said shaft and said slideway, whereby said inner edge portions are engageable with said shaft when pressure is lacking in said high pressure chamber to maintain said hollow member in close i proximity to and in free contact with said slideway.

2. A machine for use as a pump, a compressor, blower or motor, comprising a casing. a partition dividing said casing into high and low pressure chambers, said low pressure chamber having an inlet and said high pressure chamber having an outlet, a slideway on said partition, ports in said slideway, passages in said partition and respectively in communication between said ports and said high and low pressure chambers, an eccentric, a shaft for said eccentric journalled in said casing extending parallel with and spaced from said slideway, a hollow sleeve-like member having front and rear ends with slot-like openings through its side walls and defined by edge portions which are substantially parallel with the front end of said member, said hollow member being mounted in said casing between said shaft and partition with its front end against said slideway over said ports and with said shaft within said slot-like openings, said hollow member diametrically surrounding said eccentric to be reciprocated thereby over said slideway and alternately past said ports during its reciprocatory travel to control the flow of working fluid therethrough, said member nterorly cooperating with said slideway and the enclosed periphery of said eccentric to define an expansion chamber, said slideway being on the high presusre chamber side of said partition and said eccentric and hollow member being located in said high pressure chamber with said member maintained in sealing engagement with said slideway by pressure in said chamber, said edge portions of said openings being spaced from the slidable front end of said hollow member a distance slightly less than the spacing between said shaft and said partition slideway, whereby said inner edge portions are engageable with said shaft when pressure is lacking in said high pressure chamber to maintain said hollow member in close proximity to and in free contact with said slideway.

3. A machine for use as a pump, compressor, blower or motor, comprising a casing, a partition dividing said casing into high and low pressure chambers and including a slideway, said low pressure chamber having an inlet and said high pressure chamber having an outlet, ports in said partition opening through said slideway and respectively in communication with said high and low pressure chambers, an eccentric, a shaft for said eccentric journalled in said casing extending parallel with and spaced from said slideway, a hollow sleeve-like member having front and rear ends with slot-like openings through its side walls and defined by edge portions which are substantially parallel with the front end of said member, said hollow member being mounted in said casing between said shaft and partition with its front end against said slideway over said ports and with said shaft within said slot-like openings. said hollow member diametrically surrounding said eccentric to be reciprocated thereby over said slideway and alternately past said ports during its reciprocatory travel to control the iiow of working duid therethrough, said member interiorly cooperating with said slideway and the enclosed periphery of said eccentric to define an expansion chamber, said slideway being on the high pressure chamber side of said partition and said eccentric and hollow member being located in said high pressure chamber with said member maintained in sealing engagement with said slideway by pressure in said chamber, said edge portions of said openings being spaced from the slidable front end of said hollow member a distance slightly less than the spacing between said shaft and said partition slideway, whereby said inner edge portions are engageable with said shaft when pressure is lacking in said high pressure chamber to maintain said hollow member in close proximity to and in free contact with said slideway, and spacer sealing means between the high pressure chamber part of said casing and said partition for selectively adjusting the spacing between said slideway and said shaft re1- ative to the length of said member between its front end and the said member edge portions.

4. A machine for use as a pump, compressor, blower or motor, comprising a casing, a partition dividing said casing into high and low pressure chambers, said low pressure chamber having an inlet and said high pressure chamber having an outlet, an element-defining a slideway removably mounted on said partition, ports in said slideway element, passages in said partition and respectively in communication between said ports and said high and low pressure chambers, an eccentric, a shaft for said eccentric journalled in said casing extending parallel with and spaced from said slideway, a hollow sleeve-like member having front and rear ends with slot-like openings through its side walls and dened by edge portions which are substantially parallel with the front end of said member, said hollow member being mounted in said casing between said shaft and element with its front end against said slide- Way over said ports and with said shaft within 6. said slot-like openings, said hollow member diametricaliy surrounding said eccentric to be reciprocated thereby over said slideway and alternately past said ports during its reciprocatory travel to control the flow of working fluid therethrough, said member interiorly cooperating with said slideway and the enclosed periphery of said eccentric to define an expansion chamber, said slideway element being on the high pressure chamber side of said partition and said eccentric and hollow member being located in said high pressure chamber with said member maintained in sealing engagement with said slideway by pressure in said chamber, said edge portions of said openings being spaced from the slidable front end of said hollow member a distance slightly less than the spacing between said shaft and said slideway. whereby said inner edge portions are engageable with said shaft when presi sure is lacking in said high pressure chamber to maintain said hollow member in close proximity to and in free contact with said slideway, and spacer sealing means between the slideway element and partition and between the high pressure chamber part of said casing and said partition for selectively adjusting the spacing between said slideway and said shaft relative to the length of said member between its front end and the said member edge portions.

5. A machine for use as a pump, compressor, blower or motor, comprising a casing, a partition dividing said casing into high and low pressure chambers, said low pressure chamber having an inlet and said high pressure chamber having an outlet, an element defining a slideway removably mounted on said partition, ports in said element, passages in said partition and respectively in communication between said 'ports and said high and low pressure chambers, an eccentric, a shaft for said eccentric journalled in said casing extending parallel with and spaced from said slideway, a hollow sleeve-like member having `front andA rear ends with slot-like Vopenings through its side walls and defined by 'edge portions which 'are substantially parallel with the front end of said member, said hollow member being mounted in said casing between said shaft and element with its front end against said slideway over said ports and with said shaft within said slot-like openings, said hollow member diametrically surrounding said eccentric to be reciprocatedthereby over said slideway and alternately past said ports during its reciprocatory travel to control the flow of working fluid therethrough, said member interiorly cooperating with said slideway and the enclosed periphery of said eccentric to define an expansion chamber, said slideway element being on the high pressure chamber side of said partition and said eccentric and hollow member being located in said high pressure chamber with said member maintained in sealing engagement with said slideway by pressure in said chamber, said edge portions of said openings being spaced from the slidable front end of said hollow member a distance slightly less than the spacing between said shaft and said slideway, whereby said inner edge portions are engageable with said shaft when pressure is lacking in said high pressure chamber to maintain said hollow member in close proximity to and in free contact with said slideway, and spacer sealing means between the slideway element and partition for selectively adjustingV the spacing between said slideway and said shaft relative to the length of said member between its UNITED STATES PATENTS front endend the said member edge DOIUOPS- Number Name Date FREDERICK WALTER MCCOMBIE- A'179,900 Bartlett Jan.10,1905 REFERENCES CITED 1,240,211 Hrath S-ept. 18, 1917 The following references are of record in the FOREIGN IPATENTS me t this patent: Number Country Date Y 592,432 Great Britain Sept. 17, 1947 862.170 France Nov. 30, 1940 

